| Message ID | 20231129152307.28517-1-boerge.struempfel@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] gpiolib: sysfs: Fix error handling on failed export | expand |
On Wed, Nov 29, 2023 at 04:23:07PM +0100, Boerge Struempfel wrote: > If gpio_set_transitory() fails, we should free the GPIO again. Most > notably, the flag FLAG_REQUESTED has previously been set in > gpiod_request_commit(), and should be reset on failure. > > To my knowledge, this does not affect any current users, since the > gpio_set_transitory() mainly returns 0 and -ENOTSUPP, which is converted > to 0. However the gpio_set_transitory() function calles the .set_config() > function of the corresponding GPIO chip and there are some GPIO drivers in > which some (unlikely) branches return other values like -EPROBE_DEFER, > and -EINVAL. In these cases, the above mentioned FLAG_REQUESTED would not > be reset, which results in the pin being blocked until the next reboot. Thank you! Reviewed-by: Andy Shevchenko <andy@kernel.org>
On Wed, Nov 29, 2023 at 4:23 PM Boerge Struempfel <boerge.struempfel@gmail.com> wrote: > > If gpio_set_transitory() fails, we should free the GPIO again. Most > notably, the flag FLAG_REQUESTED has previously been set in > gpiod_request_commit(), and should be reset on failure. > > To my knowledge, this does not affect any current users, since the > gpio_set_transitory() mainly returns 0 and -ENOTSUPP, which is converted > to 0. However the gpio_set_transitory() function calles the .set_config() > function of the corresponding GPIO chip and there are some GPIO drivers in > which some (unlikely) branches return other values like -EPROBE_DEFER, > and -EINVAL. In these cases, the above mentioned FLAG_REQUESTED would not > be reset, which results in the pin being blocked until the next reboot. > > Fixes: e10f72bf4b3e ("gpio: gpiolib: Generalise state persistence beyond sleep") > Signed-off-by: Boerge Struempfel <boerge.struempfel@gmail.com> > > --- > > V2: https://lore.kernel.org/linux-gpio/CAEktqcv8NC0Cy+wo7nRGOp9USoBdta=n=mrbo-WomxgcmWN5nQ@mail.gmail.com/T/#t > V1: https://lore.kernel.org/linux-gpio/CAEktqcuxS1sPfkGVCgSy1ki8fmUDmuUsHrdAT+zFKy5vGSoKPw@mail.gmail.com/T/#t > > Changes from V2: > - Capitalized all occurances of GPIO in commit message > - Added Missing - in front of Error Code in commit message > - Added Fixes Tag in commit message > > Changes from V1: > - Marked all functions in commit message with parenthesis > - Elaborated in commit message > > drivers/gpio/gpiolib-sysfs.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c > index 6f309a3b2d9a..12d853845bb8 100644 > --- a/drivers/gpio/gpiolib-sysfs.c > +++ b/drivers/gpio/gpiolib-sysfs.c > @@ -474,14 +474,17 @@ static ssize_t export_store(const struct class *class, > goto done; > > status = gpiod_set_transitory(desc, false); > - if (!status) { > - status = gpiod_export(desc, true); > - if (status < 0) > - gpiod_free(desc); > - else > - set_bit(FLAG_SYSFS, &desc->flags); > + if (status) { > + gpiod_free(desc); > + goto done; > } > > + status = gpiod_export(desc, true); > + if (status < 0) > + gpiod_free(desc); > + else > + set_bit(FLAG_SYSFS, &desc->flags); > + > done: > if (status) > pr_debug("%s: status %d\n", __func__, status); > -- > 2.42.0 > Applied, thanks! Bart
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index 6f309a3b2d9a..12d853845bb8 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -474,14 +474,17 @@ static ssize_t export_store(const struct class *class, goto done; status = gpiod_set_transitory(desc, false); - if (!status) { - status = gpiod_export(desc, true); - if (status < 0) - gpiod_free(desc); - else - set_bit(FLAG_SYSFS, &desc->flags); + if (status) { + gpiod_free(desc); + goto done; } + status = gpiod_export(desc, true); + if (status < 0) + gpiod_free(desc); + else + set_bit(FLAG_SYSFS, &desc->flags); + done: if (status) pr_debug("%s: status %d\n", __func__, status);
If gpio_set_transitory() fails, we should free the GPIO again. Most notably, the flag FLAG_REQUESTED has previously been set in gpiod_request_commit(), and should be reset on failure. To my knowledge, this does not affect any current users, since the gpio_set_transitory() mainly returns 0 and -ENOTSUPP, which is converted to 0. However the gpio_set_transitory() function calles the .set_config() function of the corresponding GPIO chip and there are some GPIO drivers in which some (unlikely) branches return other values like -EPROBE_DEFER, and -EINVAL. In these cases, the above mentioned FLAG_REQUESTED would not be reset, which results in the pin being blocked until the next reboot. Fixes: e10f72bf4b3e ("gpio: gpiolib: Generalise state persistence beyond sleep") Signed-off-by: Boerge Struempfel <boerge.struempfel@gmail.com> --- V2: https://lore.kernel.org/linux-gpio/CAEktqcv8NC0Cy+wo7nRGOp9USoBdta=n=mrbo-WomxgcmWN5nQ@mail.gmail.com/T/#t V1: https://lore.kernel.org/linux-gpio/CAEktqcuxS1sPfkGVCgSy1ki8fmUDmuUsHrdAT+zFKy5vGSoKPw@mail.gmail.com/T/#t Changes from V2: - Capitalized all occurances of GPIO in commit message - Added Missing - in front of Error Code in commit message - Added Fixes Tag in commit message Changes from V1: - Marked all functions in commit message with parenthesis - Elaborated in commit message drivers/gpio/gpiolib-sysfs.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)